Frederico Gutierrez, Mitul SahaFrederico Gutierrez, Mitul Saha

Yong Song and Anna TimbieYong Song and Anna Timbie

Guidant mentorsGuidant mentors:: David Wolf-Bloom, Stephanie SzobotaDavid Wolf-Bloom, Stephanie Szobota

Stanford mentorsStanford mentors:: Dr. Charles Taylor, Chris ElkinsDr. Charles Taylor, Chris Elkins

February 10, 2003February 10, 2003

Project Plan Project Plan PresentationPresentation

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Guidant CorporationGuidant Corporation, Vascular , Vascular InnovationsInnovations

Guidant is a leader in the design Guidant is a leader in the design and development of and development of cardiovascular medical productscardiovascular medical products

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MotivationMotivation

The development of medical devices The development of medical devices is limited by the ability of designers is limited by the ability of designers to evaluate them before human use.to evaluate them before human use.

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Preclinical Test MethodsPreclinical Test Methods

Animal studiesAnimal studies• ExpensiveExpensive• Unfeasible for high-Unfeasible for high-

volumevolume• Ethical considerationsEthical considerations

Simple plastic Simple plastic modelsmodels

Cannot replicateCannot replicate• in vivoin vivo conditions conditions• Human disease stateHuman disease state

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Synthetic Arterial ModelSynthetic Arterial Model

• Simplified human “knee to neck” anatomySimplified human “knee to neck” anatomy• Tissue simulating materialsTissue simulating materials• Perfused with water or blood from pumpPerfused with water or blood from pump

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SAMSAM

BenefitsBenefits• FluorcompatibleFluorcompatible• Modular, “plug-n-play”Modular, “plug-n-play”• PortablePortable

LimitationsLimitations• Static flow (roller Static flow (roller

pump)pump)• Static heartStatic heart• No respiratory No respiratory

movementmovement

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Project GoalsProject Goals To improve the clinical realism of the To improve the clinical realism of the

Guidant SAM by incorporating new Guidant SAM by incorporating new design featuresdesign features• Pulsatile flow through the vasculature Pulsatile flow through the vasculature • Coronary Artery and Heart Wall MotionCoronary Artery and Heart Wall Motion• Respiratory MotionRespiratory Motion

Provide Guidant with a tool for Provide Guidant with a tool for product testing and physician trainingproduct testing and physician training

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Project ScopeProject Scope

• Heart wall motion and pulsatile flow Heart wall motion and pulsatile flow need not be coupledneed not be coupled

• Anatomical realism of internal heart Anatomical realism of internal heart structure not necessarystructure not necessary

• Flow rate and pressure within 10% Flow rate and pressure within 10% of published valuesof published values

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DeliverablesDeliverables

1.1. System for regulation of pulsatile System for regulation of pulsatile flow from Harvard Pump through flow from Harvard Pump through arterial modelarterial model

2.2. Prototype of mechanism to produce Prototype of mechanism to produce heart wall motionheart wall motion

3.3. System for synchronization of heart System for synchronization of heart “beat” and pulsatile flow“beat” and pulsatile flow

4.4. Prototype of mechanism to produce Prototype of mechanism to produce diaphragm motiondiaphragm motion

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BenchmarkingBenchmarking

Vascular ModelsVascular Models• Consist of Rigid Consist of Rigid

ElementsElements• No Plug-n-Play No Plug-n-Play

AbilitiesAbilities• Does Not Incorporate Does Not Incorporate

Pulsatile FlowPulsatile Flow

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BenchmarkingBenchmarking

• Beating Heart Beating Heart ModelsModels– The The Chamberlain GroupChamberlain Group

• Training model for Training model for beating heart surgerybeating heart surgery

• Electrically poweredElectrically powered• Uses Pneumatic Coils to Uses Pneumatic Coils to

Create MotionCreate Motion• Suturable Exterior SkinSuturable Exterior Skin• Not FluorocompatibleNot Fluorocompatible

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BenchmarkingBenchmarking Mechanical Left Mechanical Left

A/V modelA/V model• Provides realistic Provides realistic

flow and flow and pressures of the pressures of the left A/V left A/V

• Can be used to Can be used to calibrate flow for calibrate flow for mechanical heartsmechanical hearts

• Not anatomically Not anatomically realisticrealistic

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Related TechnologyRelated Technology

Harvard PumpHarvard Pump• Generates Pulsatile Generates Pulsatile

FlowFlow• Adjustable Flow Adjustable Flow

Rates and Stroke Rates and Stroke VolumeVolume

• Physiologically Physiologically Accurate MotionAccurate Motion

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Related TechnologyRelated Technology

Flexible MoldingFlexible Molding• Casting Polyurethane Casting Polyurethane

and Silicone Materialsand Silicone Materials• Relatively low Relatively low

prototyping costprototyping cost• Materials range from Materials range from

Hardness of 10-95 Hardness of 10-95 (Shore A)(Shore A)

• Flexibility of up to Flexibility of up to 1000% original size1000% original size

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Critical Design Critical Design RequirementsRequirements

FunctionalFunctional

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Critical Design Critical Design RequirementsRequirements

FunctionalFunctional• Pulsatile flow through the Pulsatile flow through the

vasculaturevasculature

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Critical Design Critical Design RequirementsRequirements

FunctionalFunctional• Pulsatile flow through the Pulsatile flow through the

vasculaturevasculature• Realistic flow rate and pressure in the Realistic flow rate and pressure in the

major arteriesmajor arteries

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Critical Design Critical Design RequirementsRequirements

FunctionalFunctional• Pulsatile flow through the Pulsatile flow through the

vasculaturevasculature• Realistic flow rate and pressure in the Realistic flow rate and pressure in the

major arteriesmajor arteries• Heart wall motionHeart wall motion

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Critical Design Critical Design RequirementsRequirements

FunctionalFunctional• Pulsatile flow through the Pulsatile flow through the

vasculaturevasculature• Realistic flow rate and pressure in the Realistic flow rate and pressure in the

major arteriesmajor arteries• Heart wall motionHeart wall motion• Synchronization of Synchronization of

Pulsatile flow and Pulsatile flow and

Heart wall motionHeart wall motion

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Critical Design Critical Design RequirementsRequirements

PhysicalPhysical• Fluoro-compatibleFluoro-compatible

• Approximate size Approximate size and shape of human and shape of human heartheart

• Interface with Interface with aortic tree and aortic tree and coronary arteriescoronary arteries

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Critical Design Critical Design RequirementsRequirements

PhysicalPhysical• Fluoro-compatibleFluoro-compatible

• Approximate size Approximate size and shape of and shape of human hearthuman heart

• Interface with Interface with aortic tree and aortic tree and coronary arteriescoronary arteries

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Critical Design Critical Design RequirementsRequirements

PhysicalPhysical• Fluoro-compatibleFluoro-compatible

• Approximate size Approximate size and shape of human and shape of human heartheart

• Interface with Interface with aortic tree and aortic tree and coronary arteriescoronary arteries

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Critical Design Critical Design RequirementsRequirements

PhysicalPhysical• Fluoro-compatibleFluoro-compatible

• Approximate size Approximate size and shape of and shape of human hearthuman heart

• Interface with Interface with aortic tree and aortic tree and coronary arteriescoronary arteries

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DesirablesDesirables

• Diaphragm movementDiaphragm movement• Adjustable heart rate (70-120 Adjustable heart rate (70-120

bpm)bpm)• Adjustable vessel pressureAdjustable vessel pressure• Easy “plug-n-play”Easy “plug-n-play”• Simulation of cardiovascular Simulation of cardiovascular

diseasedisease

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Expected DifficultiesExpected Difficulties

• Achieving accurate pressure and Achieving accurate pressure and flow through entire modelflow through entire model

• Molding of flexible heartMolding of flexible heart• Leakage due to material Leakage due to material

incompatibilitiesincompatibilities• Air trapped in modelAir trapped in model• System integration and controlsSystem integration and controls

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Timeline (Winter) Timeline (Winter)

• 2/2 ~ 2/212/2 ~ 2/21 Design Beating Heart Design Beating Heart

• 2/10 ~ 2/192/10 ~ 2/19 Analytical Flow ModelAnalytical Flow Model• 2/10 ~ 2/192/10 ~ 2/19 Design Lab-View SystemDesign Lab-View System• 2/28 ~ tbd2/28 ~ tbd Test and Tune Flow ModelTest and Tune Flow Model• 2/19 ~ 3/12/19 ~ 3/1 Heart Critical Function Heart Critical Function

PrototypingPrototyping• 3/1 3/1 Select Heart Design Select Heart Design • 3/10 ~ 3/143/10 ~ 3/14 Final Presentation & Report Final Presentation & Report

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Timeline (Spring)Timeline (Spring)

• Beating Heart PrototypingBeating Heart Prototyping• Diaphragm Motion Design and Diaphragm Motion Design and

PrototypingPrototyping• Total System Integration and Total System Integration and

TestingTesting• Integrate Into SAMIntegrate Into SAM• Final System TestingFinal System Testing• Final Presentation & ReportFinal Presentation & Report

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Individual Individual ResponsibilitiesResponsibilities

Eric Eric ►► Flow Modeling, Material Research, Flow Modeling, Material Research, Molding ProcessMolding Process

AnnaAnna ►► Flow Circuit Modeling, Flow TuningFlow Circuit Modeling, Flow TuningMitul Mitul ►► Data Acquisition and Control Data Acquisition and Control

SystemsSystemsSongSong ►► Harvard Pump Modification, Harvard Pump Modification,

PrototypingPrototyping

Full TeamFull Team ►► Background Research Background Research BenchmarkingBenchmarking Brainstorming Brainstorming

PrototypingPrototyping TestingTesting

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IT’S A GREAT TIME TO BE IT’S A GREAT TIME TO BE ALIVE™ALIVE™

Questions?Questions?